Apparatus for reproducing sound



Jan. 17, 1928.

W. H. PERKINS APPARATUS FOR REPRODUCING, SOUND 'Filed Sept. 18; 1920 2 Sheets-Sheet 1 AJQ L fire (Z232.

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W. H. PERKINS APPARATUS FOR REPRODUCING SOUND Filed Sept. 18. 1920 2 Sheets-Sheet 2 ji A? 3 Patented Jan. 17, 1928.

UNITED STATES PATENT'OFFICE- WILLIAM HENRY PERKINS, OF BABNSTABLE, MASSAGHUSETTS,'ASSIGNOR OF ONE- IOURTHTO GEORGE A. ROCKWELL, OF BOSTON, MASSACHUSETTS.

APPARATUS FOR REPRODUCING SOUND.

Application filed September 18, 1920. Serial No. 411,080,

In the prior art reproduction has been accomplished in most cases entirely mechanically, and in some cases transmission has been accomplished electrically but m these latter cases the development has been mechanical and not electrical and usually this development is by means of a column of air. The result is that certain sounds have not heretofore been audibly reproduced 1 at all and others have been very imperfectly reproduced, this bein mainly on accountof the slow mechanical evelopment.

The principal objects of my invention are to overcome these defects and to reproduce sounds which have not heretofore been audi bly reproduced and also to materially improve the development and transmission of other sounds which have been imperfectly reproduced.

A feature of my invention is electrical development of sound whetherrecorded permanently or to be recorded permanently, and preferably this development is entire y electrical.

Another feature is electrical means for partial or entire development of recorded sound as well as for transmission thereof.

Another feature is the combination of a record-operated diaphragm, the latter being so mechanically connected with the actuator used to vary the resistance in an electric circuit, and preferably this connection .is by direct contact and the circuit is preferably balanced this feature being particularly important if my invention 1s embodied in a phonograph.

In connection with my reference to a balanced circuit I ma explain that the effect of capacity intro uced into an alternatphase, since the reaction of a condenser instead of tending to prolong the current tends to drive it back. Since capacity and inductance produce opposite effects they can be used to neutralize each other. They exactly balance if impedance equals the inductance and if the current were led into a condenser of small capacity the current running in and out of the condenser would be governed only by capacity and frequency and not by the resistance; Variable resistance is used only to start oscillations, the condenser balancing and continuing them automatically, cutting out the resistance and 6 thus making a resonant or balanced circuit.

- said ing current circuit is to produce a lead in flange b which is interiorly threa ed to en- Another feature is a pressure or tension device to provide mechanical pressure for the actuator and to provide electrical means for controlling the amount of current suitable for the development and transmission desired,

Another feature is the construction of sald pressure or tension device.

Another feature is a rigid arm to actuate the diaphragm, which arm has a fixed connection with'said diaphragm.

Another feature is havin the record-operated' diaphragm .preferab y of the same size as the receiver diaphragm.

Another feature is the combining of the receiver with the case containing the diaphragm and microphone in one compact structure.

Another feature is a switch controlled by a brake, the latter controlling the mechanism which operates the record.

. Other features will be pointed out below.

Figure 1 is a central vertical section of a phonograph in which my invention is em- I bodied; 80

Figure 2 is a diagrammatic view of one form of switch for making and breaking the circuit; and I Figure 3 is a dia rammatic viewflof a N phonograph of a different form; and

Figure 4 is a modification described below.

I illustrate my invention as embodied in a phonograph which hasa casing in three parts A,-B and C. Part A is cylindrical and is interiorly annularly threaded at a, art A having a threaded openin a and aving side perforations. at a an a to permit entrance of the wires as described below. Part B has a dependin annular part B engagin the top of part A and being exteriorly t readed, at I; this threading .o

engaging the interior threadin of cat-ppart C which is screwed down to ho 1 metal diaphragm' D in place between annular washers D and D of fibre or other suit-able material, the cap- Ghaving a threaded perforation c to aid in holding t e tone arm as described below. t Upon the bottom of art A rests annular washer E of fibreor 0t er suitable material supporting mica diaphragm E and upon the latter is p aced washer similar to washer E, these two washers and the diaphragm no being held in position by ring E exteriorly threaded to engage threadin a.

Member F is held to mem r A by screws I f f and has a central perforation f to erforation a .Screw Gr holds carbon contact plate G metal plate G and flat button Gr to diaphragm G said button being the actuator of said actuating mechanism for varying electrical resistance, and being in direct contact with diaphragm E so as to partake of all the movement of said diaphragm. Wire H is suitably connected to metal plate G and runs out through perforation a.

A rigid steel needle J is held firmly to diaphragm E by cement J and the cement is preferably held in place by a mica cup J perforated centrally to receive the shank of said needle, which is pivotally connected to one end of lever J the other end carrying a diamond point J 4 moved by the indentations, undulations or other recording to, sai

i F is held by threading a.

character on the record cylinder K," which has sound directly recorded thereon and which is mounted to rotate on shaft K. Lever J a is pivotally mountedat J on member J 6 connected through flat spring J T with member J member J having a yoke J to engage pin J on member J and thereby limit the movement of member J Member J 8 has an interiorly threaded perforation to engage the exterior threading of tube J which is exteriorly threaded to engage the ortion G has a collarF' fixed there'- collar serving'as one abutment of spring F coiled around ortion G the top of member F serving as t e other abutment, and 1n this way I provide a very efiici'ent ten- S1011 or pressure evice. A bridge member screws-F, F to member F The has a t which bears upon and adjusts ortion G.

.Thebalanced circuit which, prefer comthe induction coil; wire wire H; switch H; wire H and wire H prises wire *H' wireH bein the prinia of II; battery I-I;

and the electrical actuating mechanism; and

also includes wire H, beingthe secondary of the induction coil, and wires H and H"? running to the receiver coils M and M';'and also includes condenser H. H, is referably used in the secondary of the in' action coil so as .not to the of said iaphragm :bination with the'balanced circuit and parreaded passage for screw F9 v ticularly when also combined with m .ten-

A rhe'ostat character or quality of the reproduced soundbut to reduce the volume to the degree desired. The receiver coils M and M are sup- In view of my use of electrical means it is desirable that the circuit be made only when the sound is being reproduced and I therefore prefer to use a switch of the character shown in Figure 2 in which N represents the rotary member to carry the record and N represents the brake, compression spring N tending in the position shown, to hold the brake against member N. .When. brake N is swung out of contact with member N said spring slides along slot 1 and tends to hold the brake out of contact with the rotary member. Brake N carries a bridge piece n insulated at 71/ the bridge iece being electrically connected with wire corre'sp'ondin with wire H of Figure 1. When the bra e is swung out of contact with member N it carries bridge piece n into contact with terminal n, insulated at n from, but connected to, support n, said terminal being electrically connected with wire H, corresponding to wire H of Figure 1.- With this construction the circuit can only be made when the rotary member is freed'for operation. I In Figure 3 I show diagrammatically m apparatus used with a record plate or dis instead of a record c linder, the plate P actuating the needle which may bear against a fulcrum P, the dia hragm, corresponding with diaphragm E' in Figure 1, being vertical, instead of horizontal as in Fi re 1. I

n.using my a paratus it will be clear that the sound recor ed on the cylinder K will be low reproduced by the diaphragm E and will then be reproduced, developed and transmit ted b in electrical means the direct contact with the button in com-' sion device producing results never fore attained, particularly in automatic music.

As instances of these results I ma point out that the record of the sound 0 a bass drum has been fully re roduced and developed'b the tests ma" e withemy apparatus w e such sound has never been andibly tests have produced before and my reproduced with marvelous c earness the music of a piano while it'is well known that the reproduction of such music has heretofore been extremely indistinct and unsatis- One reason that I am able to factory. accomplish my results is that I use electrical means to develop the record sound, that is to sa the complete record of the sound is made audible whereas, when mechanical development is attempted, all the recorded sound is not made audible or at least is not distinctly audible-and one reason for this is that mechanical devolopment is too slow and also, as in the case of a column of air, some of the sound is dissipated in development and not conserved as in my apparatus. I

A particular feature of advantage of my apparatus is that the actuator is held under pressure against the diaphragm E under all conditions of vibration, this being due to the adjusting screw F", the diaphra m G vibrating in synchrony with diap ragm E during such holding under pressure, and this pressure is preferably longitudinal and substantially in line with needle J to keep the actuator in line with the needle J. The spring F holds portion G firmly against screw F.

In Figure 4 I have shown my invention embodied in an apparatus in which the sound enterin the horn R vibrates mica diaphragm Rw iich is indirect contact under pressure with button R which is part of the actuating mechanism for the electric circuit, the wires of the circuit leading to the receiver coils R and R which .vibrate dia phragm R and thereby needle R and consequently recording point R which permanently records the sound'on rotary record cylinder R The parts of Figure 4 to which reference characters have not been applied. are the same asthe corresponding parts of Figure 1 and it is therefore considered unnecessary to describe themin detail. It will be clear that in Figure 4 the sound of the voice or musical instrument or other sound iVhat I claim is: 1. An apparatus for reproducing sound comprising a die hragm; an electric circuit for developing t e sound recorded on said diaphragm; actuating means for said circuit; a casin for said actuating means; a screw to ad ust said casing to hold said actuating means in contact with said diaphragm under pressure; and resilient means to hold said casing incontact with said screw.

2. An apparatus for reproducing sound comprising an electric circuit for reproducing sound; a movable member adapted to carr a record; and another movable member having a portion which acts directly as a brake for the record-carr ing member and also having a portion which to control the making of said circuit.

3. .An apparatus for reproducing sound comprisin an electric circuit; a movable member a apted to carry a rccord; another movable member havin connected to it whic normally olds acts as a bridge n o n I a portion r1 idly the record-carrying member mechanically against movement, said other movable memher having another portion rigidly connected to it which acts directly as a brid e to make said circuit when said first-mentioned portion is moved to release the record-carrying member; and means to hold said other member with the first-mentioned portion in its position'of release.

4-. An apparatus for reproducing sound comprising a diaphragm; means to old the edge of said diaphragm stationary; a member having sound recorded thereon; mechanical means to reproduce on said diaphragm the sound recorded on said memberan electric circuit for developing the sound recorded on said diaphragm; a microphone, including a casing, separate from said diaphragm and having a flexible element; an actuator. having fixed connection with said flexible element but unconnected to said diaphragm for varying the resistance in said circuit; a screw to adjust said casing to hold said actuator in contact with said diaphragm. under pressure; and resilient means to hold said casing in contact with said screw.

WILLIAM HENRY PERKINS. 

